Snowmobiles, ATVs, and related vehicles (hereinafter, “recreational vehicles,” although the appellation should not be construed to be limited only to the vehicles or type of vehicles described herein) often function under similar operating conditions. Despite this, snowmobiles, ATVs, and other recreational vehicles often do not share a common design approach or a commonality of components. This is due, in large part, to the different stresses and strains (mainly at the extremes) that the different vehicles experience during routine operation.
Specifically, snowmobiles are designed with frame assemblies and suspensions that easily absorb the shock of obstacles encountered on groomed trails and in deep snow. They are also designed to handle the forces generated when the snowmobile is driven aggressively (e.g., under racing conditions). In addition, their frame assemblies are designed to provide optimum steering and performance in snow, whether on groomed snowmobile trails (packed snow) or in ungroomed, off-trail areas (powder or natural snow).
ATVs, on the other hand, are designed with suspensions and frame assemblies that are expected to absorb the type of momentarily intense forces associated with more rugged terrain, specifically of the type encountered in forests and woodland environments. In addition, an ATV frame is designed to withstand forces associated with significant torsional stresses that are typical when an ATV straddles large objects or when the wheels are disposed at different elevations because of the extreme terrain in which the ATV often operates.
It should be kept in mind that the design parameters of the frame assemblies for these two vehicles are also different. In a snowmobile, the frame at the rear of the vehicle is only about 15 inches wide. This is sufficient to cover the endless track that propels the vehicle and to provide a seating area for the driver. The narrow width, however, imposes certain design restrictions on the vehicle. ATVs, on the other hand, are designed with a significantly wider base, which is typically 50 inches or more. This width also imposes certain design restrictions on the ATV.
Snowmobiles and ATVs are also'designed with different centers of gravity. In the typical snowmobile, the center of gravity is very low. This assists the snowmobile rider when he or she is on a slope or in a turn because the snowmobile will naturally resist the tendency to lean or tip. ATVs, on the other hand, like off-road trucks and the like, are expected to traverse taller objects. Accordingly, their frames are designed so that the engine and seating area is further from the ground than a snowmobile. Thus, ATVs have higher centers of gravity.
Naturally, since both vehicles are designed with off-road use in mind, there are similarities between the two. Both are provided with rugged frames. Moreover, both are provided with strong suspensions. Despite this, there have been few vehicles designed that capitalize on these similarities.
Recognizing this basic similarity between the two vehicles, some after-market designers have developed kits that permit snowmobiles to be converted to ATVs and vice-versa. However, such kits are limited in their effectiveness because the two vehicles are so completely different from one another in their basic designs. The resulting, converted vehicles suffer from drawbacks that are associated with the purpose for which the primary vehicle was designed. For example, a snowmobile converted to an ATV is not expected to be able to traverse the same type of terrain as a pure ATV. Similarly, an ATV that has been converted to a snowmobile is not expected to be able to traverse the same terrain that a pure snowmobile can.
Partly due to the consumer's use of snowmobiles in the winter and ATVs in the summer, the evolution of both snowmobiles and ATVs has converged in recent years. Also, in recent years, designers have begun to apply the same basic design concepts to both vehicle types. What has resulted is a recognition that vehicles may be designed that incorporate many of the same structural elements and follow very similar design approaches.
The basis for the present invention stems from this basic recognition.